I have a question about electric guitar reamping. Given a guitar signal
recorded through the signal chain below:

Guitar - DI Box - Mic Preamp - DAW

How do I then take the track in the DAW and get it back to an
instrument-level signal that I can plug into a guitar rig? Do I simply run
it back through the same signal chain, going the opposite direction through
the DI Box?

And is the way I'm recording the dry signal the best way? Is there a better
way to record and reamp for maximum fidelity?

Thank you,
Tim

Never mind, I answered my own question.

http://www.radialeng.com/di-xamp.htm


"Noise Farm" wrote in message
...
I have a question about electric guitar reamping. Given a guitar signal
recorded through the signal chain below:

Guitar - DI Box - Mic Preamp - DAW

How do I then take the track in the DAW and get it back to an
instrument-level signal that I can plug into a guitar rig? Do I simply
run it back through the same signal chain, going the opposite direction
through the DI Box?

And is the way I'm recording the dry signal the best way? Is there a
better way to record and reamp for maximum fidelity?

Thank you,
Tim

http://www.littlelabs.com/redeye.html

Noise Farm wrote:

Never mind, I answered my own question.

http://www.radialeng.com/di-xamp.htm


"Noise Farm" wrote in message
...

I have a question about electric guitar reamping. Given a guitar signal
recorded through the signal chain below:

Guitar - DI Box - Mic Preamp - DAW

How do I then take the track in the DAW and get it back to an
instrument-level signal that I can plug into a guitar rig? Do I simply
run it back through the same signal chain, going the opposite direction
through the DI Box?

And is the way I'm recording the dry signal the best way? Is there a
better way to record and reamp for maximum fidelity?

Thank you,
Tim

Noise Farm wrote:
How do I then take the track in the DAW and get it back to an
instrument-level signal that I can plug into a guitar rig?

http://reamp.com/

Johann
--
Meiner Meinung nach ist ein Reply-To-Posting ohne Einleitungszeile wie
ein Ei ohne Gelb!
(Uwe Premer in )

Noise Farm wrote:

How do I then take the track in the DAW and get it back to an
instrument-level signal that I can plug into a guitar rig?

Its a matter of level, and more importantly, impedance matching.

You are correct, that it is essentially the reverse process of what the D.I.
did, however, it is only a rare few passive D.I.s that can be used in
reverse.

Try this device instead. I love it.

www.reamp.com

Good luck!

In article writes:

How do I then take the track in the DAW and get it back to an
instrument-level signal that I can plug into a guitar rig?

Its a matter of level, and more importantly, impedance matching.

Level for sure, impedance matching isn't so critical. The console will
drive anytihng - the instrument amplifier directly, the mic side of a
DI, a small loudspeaker (you get the idea). The source impedance to an
instrument amplifier makes a little difference in the sound, but since
it's all artificial at this point anyway, it's not really a big deal.

What is a big deal is that the high impedance input of an instrument
amplifier makes it easy for a long cable to be a pretty good antenna,
so running 50 feet of cable from the console in the control room to
the amplifier in the studio will work, but it might be buzzy and
noisy. This is why it's standard practice to use a transformer to
provide a balanced input for the bulk of the cable run, with just a
short cable for the high-impedance run.

But if everything is in the same room, see what happens if you just
take an output from your console or DAW and connect it through a 10
foot or so cable to the amplifier input. Keep a hand on the playback
level control (fader on the console or track level on a DAW) and start
with it pretty low. It might work out just fine.

The reason why many passive DIs hooked up backwards don't work well in
this application is twofold. First, going in that direction, it's
somewhere between a 5:1 and 10:1 step-up transformer and you don't
want to boost the voltage going into the amplifer that much above
console level - in fact most of the time you want to reduce it some.
So you need to attenuate the signal going into the DI. And if you hit
it with the full console level you'll probably saturate the
transformer (though it might be just the sound you want out of the amp
- it never hurts to try).

An active DI won't work at all because it doesn't pass signal going
from the output to the input.

Spend money on gadgets if you're so inclined, but try the simple
approach first and see if you get something you can use, and like.

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Thanks for all your input, as usual you've all been tremendously helpful.
Here's what I gather so far, please correct any mistakes you see:

balanced mic level: 150 to 600 ohms, -60dB
unbalanced mic level: 5k ohms, -60dB
unbalanced instrument level: 10M ohms, -20dB
line level (balanced): 200-800 ohms, +4dB
line level (unbalanced): 200-800 ohms, -10dB

So far here are all the reamping devices that have been mentioned in this
thread.

http://www.radialeng.com/di-xamp.htm - $199
http://www.reamp.com - $240
http://www.littlelabs.com/redeye.html - $250
http://www.littlelabs.com/ibp.html - $500

So far I'm leaning towards the redeye as it's a DI box, a reamping tool, and
a splitter.

Tim

"KyleSong" wrote in message
...
Noise Farm wrote:

How do I then take the track in the DAW and get it back to an
instrument-level signal that I can plug into a guitar rig?

Its a matter of level, and more importantly, impedance matching.

You are correct, that it is essentially the reverse process of what the
D.I.
did, however, it is only a rare few passive D.I.s that can be used in
reverse.

Try this device instead. I love it.

www.reamp.com

Good luck!





----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Noise Farm wrote:
Thanks for all your input, as usual you've all been tremendously helpful.
Here's what I gather so far, please correct any mistakes you see:

balanced mic level: 150 to 600 ohms, -60dB
unbalanced mic level: 5k ohms, -60dB
unbalanced instrument level: 10M ohms, -20dB
line level (balanced): 200-800 ohms, +4dB
line level (unbalanced): 200-800 ohms, -10dB

dB with respect to WHAT?

Note that whether something is balanced or not has nothing to do with the
operating level. Plenty of stuff works on consumer levels with balanced
lines, or professional levels with unbalanced lines.

So far here are all the reamping devices that have been mentioned in this
thread.

http://www.radialeng.com/di-xamp.htm - $199
http://www.reamp.com - $240
http://www.littlelabs.com/redeye.html - $250
http://www.littlelabs.com/ibp.html - $500

So far I'm leaning towards the redeye as it's a DI box, a reamping tool, and
a splitter.

There isn't all THAT much going on inside these boxes. I keep saying that
I am going to do a DIY project article on building one. Any of the above
will work just fine, although some of them are more convenient than others
(in part, it's very nice to have wide level controls on the box so that you
can use the amp at whatever gain setting it sounds best at without spending
a lot of time fiddling with gains on the console).
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Sat, 11 Dec 2004 19:40:36 GMT, KyleSong
wrote:


You are correct, that it is essentially the reverse process of what the D.I.
did, however, it is only a rare few passive D.I.s that can be used in
reverse.

And which would those be?

Al

balanced mic level: 150 to 600 ohms, -60dB
unbalanced mic level: 5k ohms, -60dB
unbalanced instrument level: 10M ohms, -20dB
line level (balanced): 200-800 ohms, +4dB
line level (unbalanced): 200-800 ohms, -10dB

dB with respect to WHAT?

Whatever hypothetical "0 dB" they relate to when one comes across them in
user manuals is beyond me - maybe you can help here. I'm trying to get a
general idea of what kind of conversion has to be done to reamp a guitar
signal. From what I've gathered so far, given unity gain signal paths (from
the electric guitar through the DI box through the mixer through the
converter and into the DAW, and back out through the converter and the
Reamping device into the amp) it'd be somewhere in the neighborhood of
a -24dB drop in signal and a change of impedance from roughtly 200 ohms to
10M ohms. Is this a reasonable estimate?

Scott, what is a good reference to get the basics of what is actually
happening in microphone, instrument, and line-level cables? How does the
line level relate to voltage relate to impedance, the difference between
balanced and unbalanced, etc. There must be an audio cable 101 FAQ online
or some kind of seminal reference work indispensable to electronics-impaired
novices like me.

There isn't all THAT much going on inside these boxes. I keep saying that
I am going to do a DIY project article on building one.

That would be absolutely wonderful as I'm sure the components required to
build one are far less than $199.

Thanks again,
Tim

Noise Farm wrote:
balanced mic level: 150 to 600 ohms, -60dB
unbalanced mic level: 5k ohms, -60dB
unbalanced instrument level: 10M ohms, -20dB
line level (balanced): 200-800 ohms, +4dB
line level (unbalanced): 200-800 ohms, -10dB

dB with respect to WHAT?

Whatever hypothetical "0 dB" they relate to when one comes across them in
user manuals is beyond me - maybe you can help here.

Some of those are probably supposed to be dBu, some of them are probably
supposed to be dBm.

I'm trying to get a
general idea of what kind of conversion has to be done to reamp a guitar
signal. From what I've gathered so far, given unity gain signal paths (from
the electric guitar through the DI box through the mixer through the
converter and into the DAW, and back out through the converter and the
Reamping device into the amp) it'd be somewhere in the neighborhood of
a -24dB drop in signal and a change of impedance from roughtly 200 ohms to
10M ohms. Is this a reasonable estimate?

There may actually be no drop in signal... in some cases there may be a rise
in signal voltage. That's why the better reamp boxes have a huge range of
level control. The problem is first of all that guitar pickup output levels
are all over the place from one model to the other... the problem is also
that consumer audio output levels are also all over the place.

Scott, what is a good reference to get the basics of what is actually
happening in microphone, instrument, and line-level cables? How does the
line level relate to voltage relate to impedance, the difference between
balanced and unbalanced, etc. There must be an audio cable 101 FAQ online
or some kind of seminal reference work indispensable to electronics-impaired
novices like me.

The Yamaha Sound Reinforcement Handbook is probably a good place to start,
but the FAQ for this newsgroup has a nice introduction to some of this stuff.
And I bet the Rane website has some info also, and their discussion on
interconnecting cables is worth reading.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

The schematic and circuit description for the Reamp box
can be viewed here.
http://patft.uspto.gov/netacgi/nph-P...&RS=PN/6005950

If anyone has a source for the 500ohm to 30K ohm
UTC-0-10 transformer let us know.

Goober

"Scott Dorsey" wrote in message
...
: Noise Farm wrote:
: Thanks for all your input, as usual you've all been
tremendously helpful.
: Here's what I gather so far, please correct any
mistakes you see:
:
: balanced mic level: 150 to 600 ohms, -60dB
: unbalanced mic level: 5k ohms, -60dB
: unbalanced instrument level: 10M ohms, -20dB
: line level (balanced): 200-800 ohms, +4dB
: line level (unbalanced): 200-800 ohms, -10dB
:
: dB with respect to WHAT?
:
: Note that whether something is balanced or not has
nothing to do with the
: operating level. Plenty of stuff works on consumer
levels with balanced
: lines, or professional levels with unbalanced lines.
:
: So far here are all the reamping devices that have
been mentioned in this
: thread.
:
: http://www.radialeng.com/di-xamp.htm - $199
: http://www.reamp.com - $240
: http://www.littlelabs.com/redeye.html - $250
: http://www.littlelabs.com/ibp.html - $500
:
: So far I'm leaning towards the redeye as it's a DI
box, a reamping tool, and
: a splitter.
:
: There isn't all THAT much going on inside these
boxes. I keep saying that
: I am going to do a DIY project article on building
one. Any of the above
: will work just fine, although some of them are more
convenient than others
: (in part, it's very nice to have wide level controls
on the box so that you
: can use the amp at whatever gain setting it sounds
best at without spending
: a lot of time fiddling with gains on the console).
: --scott
: --
: "C'est un Nagra. C'est suisse, et tres, tres
precis."

In article writes:

dB with respect to WHAT?

Whatever hypothetical "0 dB" they relate to when one comes across them in
user manuals is beyond me - maybe you can help here.

In general, with audio equipment, when they leave off the reference
from the "dB" it's dBV if it's -10 and dBu if it's +4. Those are about
the only numbers you see when it comes to line levels. If you see a
number like -60 dB it's usually referring to the sensitivity of a
microphone input. For that, you really need to know how the
manufactuer does his specsmanship.

Note: All errors of a factor of ten or 1.4 are attributable to the fact
that I wrote this .5 BC (half an hour before coffee). Please accept
them in the spirit of the newsgroup and only argue about the big
stuff.

dB without a reference is gain, so "-60 dB" could mean that the mic
input has 60 dB of gain: 1V out for 1 mV (.001 V) in, or a ration of
1000/1. If the mic preamp has a nominal output level of +4 dBu (1.2 V)
and 60 dB of gain, it would require .0012V coming out of the mic to
reach that nominal level. If the preamp has a nominal output level of
-10 dBV (0.31 V) and 60 dB of gain, it would require only 0.00031 V
coming out of the mic to reach the nominal output level.

Which is "better?" It depends on what operating voltage the next stage
requires. But that's a different story.

I'm trying to get a
general idea of what kind of conversion has to be done to reamp a guitar
signal. From what I've gathered so far, given unity gain signal paths (from
the electric guitar through the DI box through the mixer through the
converter and into the DAW, and back out through the converter and the
Reamping device into the amp) it'd be somewhere in the neighborhood of
a -24dB drop in signal and a change of impedance from roughtly 200 ohms to
10M ohms. Is this a reasonable estimate?

You probably don't have to drop the level by 24 dB. Guitars can be
pretty hot when you're playing hard, upwards of a couple of volts out.
But since the source impedance is quite high, if you try to connect
a guitar pickup directly to a conventional line level input which
might have an impedance of 5K to 20K ohms, you end up dropping much of
the voltage across the pickup itself, leaving maybe 20% to go to the
console (about a 14 dB loss). But the output impedance of a console or
DAW audio interface is low and will not be affected by connecting it
to a guitar amplifier input. So all you really have to be concerned
with is:

- Dropping the level down to the point where the guitar amplifier
input either doesn't clip or clips the way you would like it to if
the actual guitar was connected to it.

and

- Getting the signal from the control room equipment to the
amplifier without picking up too much hum along the way.

A secondary (and probably minor, but you're the guitar player, not me)
consideration is how the amplifier reacts to being fed from a low
impedance source rather than a high impedance source. In the Millenia
Media Twin Direct, there are two taps on the DI output transformer so
that you have a choice of source impedances to drive the amplifier.
Throw a switch and see if it makes a difference that you care about.

Scott, what is a good reference to get the basics of what is actually
happening in microphone, instrument, and line-level cables? How does the
line level relate to voltage relate to impedance, the difference between
balanced and unbalanced, etc. There must be an audio cable 101 FAQ online
or some kind of seminal reference work indispensable to electronics-impaired
novices like me.

I wrote an article in Recording about this several years back and the
editor says it's time to recycle that thought, so if you can hold out
until late Spring you'll probably be able to read it there. The Yamaha
Sound Reinforcement Handbook (I think it's still available) has a
pretty good explanation of voltage, current and impedance
relationships (Ohm's Law) and of how dB is used in audio. Somebody
probably has written all of this up and put it on line, but there's
also probably _something_ wrong or incomplete in any one place.

There isn't all THAT much going on inside these boxes. I keep saying that
I am going to do a DIY project article on building one.

The first step in creating a DIY project (and I wrote another article
in Recording about this subject) is to figure out what problem you
need to solve. Connect your recorded source to your instrument
amplifier with a cable, play with the knobs, and see what happens.
Play with it (source output level and amplifier gain) for a while and
see what you can conclude. If you have too much hum, experiment with
grounding to see if you can make it go away by eliminating a ground
loop. Experiment. Learn. Ask questions about what you've learned.



--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

KyleSong wrote:

Noise Farm wrote:

How do I then take the track in the DAW and get it back to an
instrument-level signal that I can plug into a guitar rig?

Its a matter of level, and more importantly, impedance matching.


Impedence may not be as big a deal as it seems. Since (at least) the early
80s, most stomp box pedals have had low impedence outputs (at least
substantially lower than a typical guitar pickup). I'm looking at the
original literature that came with a Tube Screamer & a Boss CE-2 chourus.
(Yes, I'm one of those obsessive/compulsive types who never throws away any
product documentation.) Both of these units are designed to feed inputs of
10K ohms or higher. In the modern world, that's what we call consumer line
level.

Since we don't see many guitarists patching reamp devices between their
pedalboards & their amps, we can assume that most guitar amps are perfectly
happy with the lower impedence output from the pedals. And, since it's
common practice to string several boxes serially, we can assume that the
boxes themselves are also happy with the lower impedence.

As always, there are exceptions. Old germanium fuzz boxes & inductor based
wahs will sound substantially different with a lower impedence input. Then
again (speaking as a guitarist), I can't imagine trying to add wah to a
part after the fact. The passive volume & tone controls on the guitar are
also affect the loading of the pickups & have a big effect on the sound.
If you're dealing with a guitarist who uses the knobs while playing, you
won't be able to duplicate that with the controls on your DAW or mixer.

In article . net writes:

The schematic and circuit description for the Reamp box
can be viewed here.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PT
O1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm
&r=1&f=G&l=50&s1=6005950.WKU.&OS=PN/6005950&RS=PN/6005950

I give up. What kind of smartass web page is this? Initially I got a
broken QuickTime icon and a note that I had to download Quicktime
Image. So I did. Now I still get a broken QuickTime icon and a message
saying that there's no need to download new software, it's already
installed. Same in Netscape and Explorer. Is there a PDF? Or a link
directly to a file that I can download and play with?

Hard to believe that someone was actualy granted a patent on this,
but lots of stuff gets patented that seems so obvious and almost
certainly done before by many people.

If anyone has a source for the 500ohm to 30K ohm
UTC-0-10 transformer let us know.

It won't be a UTC O-10, but you can find a suitable if not exact
transformer at http://www.jensen-transformers.com


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Mike Rivers wrote:
In article . net writes:
The schematic and circuit description for the Reamp box
can be viewed here.

I give up. What kind of smartass web page is this?

I suppose you are looking at the images? They are in TIFF format.
IrfanView [1] displays TIFF files, among others.

[1] http://irfanview.com/

Johann
--
Eigentlich hast Du ein Verstaendnis ueber Plonken, welches mich auch als
Real-FAQ ueberhaupt nicht interessiert wuerde. Who cares?
(*Tönnes in )

Johann Burkard wrote:

I suppose you are looking at the images? They are in TIFF format.
IrfanView [1] displays TIFF files, among others.

[1] http://irfanview.com/

Yup - that would be where I'd expect to find the schematic. I read the
"Help" and found the reference to the TIFF viewer plug-in, installed
it, and still get the same thing. If I could download a TIFF file, I
have a program that can display it, but apparently the site doesn't let
you do that.

Oh, well, I know how to build a re-amp box if I wanted to. I was just
curious since someone pointed to this web page.

agent86 wrote:

I can't imagine trying to add wah to a
part after the fact.

Of course you're right if you're talking about playing a Wah part. There are
other applications too, like an edgy filter, which might not move during the
part. That would be something you might do while reamping?

I know I'm splitting hairs, but since i got nailed on the impedance
question, I'm grasping

KyleSong wrote:

Of course you're right if you're talking about playing a Wah part. There
are other applications too, like an edgy filter, which might not move
during the part. That would be something you might do while reamping?

I know I'm splitting hairs, but since i got nailed on the impedance
question, I'm grasping


Well, it wouldn't be something *I* would do, since I don't do that much
reamping anyway. I tend to think a decent guitarist is more qualified to
get a good guitar tone than the engineer is. In the rare situation where I
*need* to record electric guitar without an amp, I'll usually split after
the pedalboard & record one side direct & the other through a Sansamp.
Later, I might reamp either or both, but I won't put any effects between
the track & the amp.

But in broader terms, yes, if you use a wah as a stationary filter, you
would probably want to feed it with a high impedence signal so the inductor
would be operating within its designed range. If you were reamping a part
with a germanium fuzz, the same thing would apply.

I wouldn't think of it as getting nailed. My point was simply that guitar
amps aren't as picky about impedence as a lot of people think. Some
devices (like wahs, old fuzzes, and passive volume & tone controls) are
pretty fussy. The reamp box is potentially useful if you need to reamp
through one of those devices, but not really needed for just an amp.

Much appreciated Mike, you and Scott both recommended the Yamaha Sound
Reinforcement book and I acted on that. Cheers!
Tim

"Mike Rivers" wrote in message
news:znr1102857714k@trad...

In article writes:

dB with respect to WHAT?

Whatever hypothetical "0 dB" they relate to when one comes across them in
user manuals is beyond me - maybe you can help here.

In general, with audio equipment, when they leave off the reference
from the "dB" it's dBV if it's -10 and dBu if it's +4. Those are about
the only numbers you see when it comes to line levels. If you see a
number like -60 dB it's usually referring to the sensitivity of a
microphone input. For that, you really need to know how the
manufactuer does his specsmanship.

Note: All errors of a factor of ten or 1.4 are attributable to the fact
that I wrote this .5 BC (half an hour before coffee). Please accept
them in the spirit of the newsgroup and only argue about the big
stuff.

dB without a reference is gain, so "-60 dB" could mean that the mic
input has 60 dB of gain: 1V out for 1 mV (.001 V) in, or a ration of
1000/1. If the mic preamp has a nominal output level of +4 dBu (1.2 V)
and 60 dB of gain, it would require .0012V coming out of the mic to
reach that nominal level. If the preamp has a nominal output level of
-10 dBV (0.31 V) and 60 dB of gain, it would require only 0.00031 V
coming out of the mic to reach the nominal output level.

Which is "better?" It depends on what operating voltage the next stage
requires. But that's a different story.

I'm trying to get a
general idea of what kind of conversion has to be done to reamp a guitar
signal. From what I've gathered so far, given unity gain signal paths
(from
the electric guitar through the DI box through the mixer through the
converter and into the DAW, and back out through the converter and the
Reamping device into the amp) it'd be somewhere in the neighborhood of
a -24dB drop in signal and a change of impedance from roughtly 200 ohms
to
10M ohms. Is this a reasonable estimate?

You probably don't have to drop the level by 24 dB. Guitars can be
pretty hot when you're playing hard, upwards of a couple of volts out.
But since the source impedance is quite high, if you try to connect
a guitar pickup directly to a conventional line level input which
might have an impedance of 5K to 20K ohms, you end up dropping much of
the voltage across the pickup itself, leaving maybe 20% to go to the
console (about a 14 dB loss). But the output impedance of a console or
DAW audio interface is low and will not be affected by connecting it
to a guitar amplifier input. So all you really have to be concerned
with is:

- Dropping the level down to the point where the guitar amplifier
input either doesn't clip or clips the way you would like it to if
the actual guitar was connected to it.

and

- Getting the signal from the control room equipment to the
amplifier without picking up too much hum along the way.

A secondary (and probably minor, but you're the guitar player, not me)
consideration is how the amplifier reacts to being fed from a low
impedance source rather than a high impedance source. In the Millenia
Media Twin Direct, there are two taps on the DI output transformer so
that you have a choice of source impedances to drive the amplifier.
Throw a switch and see if it makes a difference that you care about.

Scott, what is a good reference to get the basics of what is actually
happening in microphone, instrument, and line-level cables? How does the
line level relate to voltage relate to impedance, the difference between
balanced and unbalanced, etc. There must be an audio cable 101 FAQ
online
or some kind of seminal reference work indispensable to
electronics-impaired
novices like me.

I wrote an article in Recording about this several years back and the
editor says it's time to recycle that thought, so if you can hold out
until late Spring you'll probably be able to read it there. The Yamaha
Sound Reinforcement Handbook (I think it's still available) has a
pretty good explanation of voltage, current and impedance
relationships (Ohm's Law) and of how dB is used in audio. Somebody
probably has written all of this up and put it on line, but there's
also probably _something_ wrong or incomplete in any one place.

There isn't all THAT much going on inside these boxes. I keep saying
that
I am going to do a DIY project article on building one.

The first step in creating a DIY project (and I wrote another article
in Recording about this subject) is to figure out what problem you
need to solve. Connect your recorded source to your instrument
amplifier with a cable, play with the knobs, and see what happens.
Play with it (source output level and amplifier gain) for a while and
see what you can conclude. If you have too much hum, experiment with
grounding to see if you can make it go away by eliminating a ground
loop. Experiment. Learn. Ask questions about what you've learned.



--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Would it be one of the 1:10 step-up transformers such as the JT-115k-EPC,
JT-115-E or JT-115K-E90 (http://www.jensen-transformers.com/mic_in.html)?

"Mike Rivers" wrote in message
news:znr1102867783k@trad...

If anyone has a source for the 500ohm to 30K ohm
UTC-0-10 transformer let us know.

It won't be a UTC O-10, but you can find a suitable if not exact
transformer at http://www.jensen-transformers.com

Scott, I've got my hands on the Yamaha sound reinforcement handbook as we
speak.

Thanks again,
Tim


"Scott Dorsey" wrote in message
...

The Yamaha Sound Reinforcement Handbook is probably a good place to start,
but the FAQ for this newsgroup has a nice introduction to some of this
stuff.
And I bet the Rane website has some info also, and their discussion on
interconnecting cables is worth reading.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Is there some kind of a relatively inexpensive measuring device that can
tell you what the voltage and impedance of an analog audio signal is? If
you could read that from the source signal of the electric guitar and from
the output of your reamping device, it might aid in assuring that the source
signal from your guitar pickups and the output of your reamping box are as
matched as you can get them, barring A/D - D/A conversion and some extra
signal noise.

I realize I'm probably being a bit silly about this when the obvious answer
is "take the output from your converter and plug it into your amp" but I'd
also be able to at least know how to get as close a match as possible and
understand what's actually happening in the process.

a good thing to look into is the Millennia Media TD-1. It's an HV-3
mic pre with high and low eq, plus re-amp features and other stuff. A
great tote-around one channel box of truly professional specs.

agent86 wrote:

I wouldn't think of it as getting nailed. My point was simply that guitar
amps aren't as picky about impedence as a lot of people think. Some
devices (like wahs, old fuzzes, and passive volume & tone controls) are
pretty fussy. The reamp box is potentially useful if you need to reamp
through one of those devices, but not really needed for just an amp.

Well, nailed or not, I'm man enough to defer to folks who know better than
I, and appreciative of learning new things. In that spirit, I do thank you
for the information!

"Mike Rivers" wrote in message
news:znr1102867783k@trad...
:
: In article
. net
writes:
:
: The schematic and circuit description for the Reamp
box
: can be viewed here.
: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PT
: O1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm
:
&r=1&f=G&l=50&s1=6005950.WKU.&OS=PN/6005950&RS=PN/60059
50
:
: I give up. What kind of smartass web page is this?
Initially I got a
: broken QuickTime icon and a note that I had to
download Quicktime
: Image. So I did. Now I still get a broken QuickTime
icon and a message
: saying that there's no need to download new software,
it's already
: installed. Same in Netscape and Explorer. Is there a
PDF? Or a link
: directly to a file that I can download and play with?

It is the US patent office web page. There is a link in
the page that tells you to download a TIFF viewer plug
in for your browser. With that viewer you can see the
diagrams in much the same way you navigate a PDF.

It took some searching but it is genuine, I guarantee
it.

Goober

It is described in the text to be 500 ohm CT to 30K SE
out.
Goober

"Noise Farm" wrote in message
...
: Would it be one of the 1:10 step-up transformers such
as the JT-115k-EPC,
: JT-115-E or JT-115K-E90
(http://www.jensen-transformers.com/mic_in.html)?
:
: "Mike Rivers" wrote in message
: news:znr1102867783k@trad...
:
: If anyone has a source for the 500ohm to 30K ohm
: UTC-0-10 transformer let us know.
:
: It won't be a UTC O-10, but you can find a suitable
if not exact
: transformer at http://www.jensen-transformers.com
:
:

Noise Farm:

You can put your ohm meter into the output of your
passive guitar output jack and see directly what it's
output impedance with different volume control
settings.

You can put your ohm meter into the input of most amps
and stomp boxes and read directly what the input
impedance is. Try with amp on and off it may change.

Watch out trying to measure output impedance of
something active like a preamp out connected to an op
amp. It may not work as well as the above passive
inputs. Usually this is just really low z line out.

Goober

"Noise Farm" wrote in message
...
: Is there some kind of a relatively inexpensive
measuring device that can
: tell you what the voltage and impedance of an analog
audio signal is? If
: you could read that from the source signal of the
electric guitar and from
: the output of your reamping device, it might aid in
assuring that the source
: signal from your guitar pickups and the output of
your reamping box are as
: matched as you can get them, barring A/D - D/A
conversion and some extra
: signal noise.
:
: I realize I'm probably being a bit silly about this
when the obvious answer
: is "take the output from your converter and plug it
into your amp" but I'd
: also be able to at least know how to get as close a
match as possible and
: understand what's actually happening in the process.

A match is not necessarily what you want for the best
tone. Actually you will need to screw around and find
what you want just like anything else.

And don't forget that an EE will tell you a good match
is having the input z about 10x higher than the driving
output z. This again is not necessarily what you want
for the best tone.

Goober
:

GoobAudio wrote:

Noise Farm:

You can put your ohm meter into the output of your
passive guitar output jack and see directly what it's
output impedance with different volume control
settings.

Actually, your ohm meter measures DC resistance. In some cases, there's
enough correlation & consistency to estimate impedence reom DC resistance.
(ie. if you read 6 ohms DC across a speaker, it's probably an 8 ohm
speaker.)

To accruately measure impedence (which typically varies with frequency) you
need to hook up some kind of oscillator & graph the resistance across the
applicable frequency range.

GoobAudio philsaudio-remove this and the wrote:
The schematic and circuit description for the Reamp box
can be viewed here.
http://patft.uspto.gov/netacgi/nph-P...&RS=PN/6005950

If anyone has a source for the 500ohm to 30K ohm
UTC-0-10 transformer let us know.

The O-10 was probably selected because it was the cheapest transformer with
the right ratio available. The Triad or Tamura equivalents will be fine. I
will say that this schematic is not necessarily what Reamp is currently using,
though.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

agent86 wrote:

Since we don't see many guitarists patching reamp devices between their
pedalboards & their amps, we can assume that most guitar amps are perfectly
happy with the lower impedence output from the pedals. And, since it's
common practice to string several boxes serially, we can assume that the
boxes themselves are also happy with the lower impedence.

They are, but SOME amps will sound different with a very high-Z source.
Some amps will also sound different with a highly reactive source. I
don't have a good grip on this yet but ask me in six months. Plenty of
other amps don't seem to care (probably because thier input Z is high
enough).
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article writes:

Is there some kind of a relatively inexpensive measuring device that can
tell you what the voltage and impedance of an analog audio signal is?

A voltmeter is a relatively inexpensive measuring device that can tell
you what the voltage coming from a source is. A signal, as such,
doesn't have an impedance, but a source or a load has an impedance.
When you understand Ohm's Law, you can use a voltmeter and a resistor
to get a pretty good idea of the magnitude of the impedance.

If
you could read that from the source signal of the electric guitar and from
the output of your reamping device, it might aid in assuring that the source
signal from your guitar pickups and the output of your reamping box are as
matched as you can get them

That's a little harder. A voltmeter is essentially for measuring
steady voltages, and unless you play an electric guitar with a bow,
the output voltage will be far from steady. An oscilloscope and an
eyeball (for observing the peak voltage and taking an eyeball average)
is a better tool for this. Oscilloscopes suitable for measuring audio
voltages and frequencies, if you have space for a fairly large
cabinet, can be very inexpensive, though very old. Hewlett Packard 130
scopes can be had at hamfests for $10 or so (and are frequently
purchased by people who sell them on eBay for $50 or so). However, as
has been pointed out here, nominal values are good enough to get what
you need. You really don't have to measure YOUR guitar other than out
of curiosity.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Noise Farm wrote:
Is there some kind of a relatively inexpensive measuring device that can
tell you what the voltage and impedance of an analog audio signal is? If
you could read that from the source signal of the electric guitar and from
the output of your reamping device, it might aid in assuring that the source
signal from your guitar pickups and the output of your reamping box are as
matched as you can get them, barring A/D - D/A conversion and some extra
signal noise.

But do you really want them matched?

After all, they are badly mismatched in most cases when a pickup is plugged
into an amp. That mismatch is where some of the sound comes from.

I realize I'm probably being a bit silly about this when the obvious answer
is "take the output from your converter and plug it into your amp" but I'd
also be able to at least know how to get as close a match as possible and
understand what's actually happening in the process.

No, ultimately you don't want the best possible match, you want to simulate
the source impedance of the pickup (both resistive and reactive).

In reality, doing this seems to make a difference on some amps and not on
others, and not a huge one anyway.

I have been fooling around with this stuff for the last couple months and
hope to get a paper out of it at some point once I really understand what
is going on. But for the most part, a 1M resistive source seems good enough
to my ears.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"agent86" wrote in message
...
: GoobAudio wrote:
:
: Noise Farm:
:
: You can put your ohm meter into the output of your
: passive guitar output jack and see directly what
it's
: output impedance with different volume control
: settings.
:
: Actually, your ohm meter measures DC resistance. In
some cases, there's
: enough correlation & consistency to estimate
impedence reom DC resistance.
: (ie. if you read 6 ohms DC across a speaker, it's
probably an 8 ohm
: speaker.)
:
: To accruately measure impedence (which typically
varies with frequency) you
: need to hook up some kind of oscillator & graph the
resistance across the
: applicable frequency range.

But he wanted quick and dirty and the method you
suggest above, although more accurate, is not quick and
dirty.

When I want to know impedance I use my FFT analyzer and
get 20 thousand phase and magnitude vectors over a
series of frequencies in the audible range and beyond.
This beats what is possible to get with an oscilator
and a resistance graph.

goober.
:
:

::
: That's a little harder. A voltmeter is essentially
for measuring
: steady voltages, and unless you play an electric
guitar with a bow,
: the output voltage will be far from steady. An
oscilloscope and an
: eyeball (for observing the peak voltage and taking an
eyeball average)
: is a better tool for this. Oscilloscopes suitable for
measuring audio
: voltages and frequencies, if you have space for a
fairly large
: cabinet, can be very inexpensive, though very old.
Hewlett Packard 130
: scopes can be had at hamfests for $10 or so (and are
frequently
: purchased by people who sell them on eBay for $50 or
so). However, as
: has been pointed out here, nominal values are good
enough to get what
: you need. You really don't have to measure YOUR
guitar other than out
: of curiosity.

A channel on the DAW makes an excellent voltage level
storage scope. You could record your playing voltage on
the output of the guitar and across a resistor in
series with your guitar and amp input into two channels
on the DAW. Then you can use a signal generator to
match the recorded voltages. You can solve for the
unknown input impedance using a voltage divider
equation or substitute the series resistor ( read
adjust a pot) until the voltage across the series
resistor ( pot ) is the same as the voltage across the
amp. At this point the input impedance of the amp is
the same as the voltage.

But this aint simple.

goober

The schematic and circuit description for the Reamp box
can be viewed here.
http://patft.uspto.gov/netacgi/nph-P...&RS=PN/6005950

The USPTO search engine predates any of the fancier mixed text formats like
..pdf, and it originally brought in .tiff files to allow it to work with
simple browsers. It was, in fact, originally coded to work with mosaic using
a tiff-reading plug-in.

If you want to grab the tiff files directly, Mike, you can use lynx or wget
to retrieve "http://patimg2.uspto.gov:80/.DImg?Docid=US006005950&PageNum=4&
IDKey=33877248E611&ImgFormat=tif" and you will get the raw file back.

The schematic is on page 4. BUT, you should know that the patent doesn't
tell you everything that is going on and there are a couple things about
this circuit that seem superfluous.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."